The Northern Ireland peace process has had its trials and it has proved surprisingly durable. It survived the Omagh bombing in 1998 and it is now being seriously tested again. We should be in no doubt whom the targets of dissident republicans are: in the first rank soldiers and policemen, but in the second, Sinn Féin and its power sharing deal with the Democratic Unionists. Not only are members of Sinn Féin in the direct line of fire from republicans who believe they have sold out. Sinn Féin's political alliance with unionism is also in danger from those who continue to argue that their commitment to power-sharing is tactical, that the security forces have been denuded, and that we should swiftly throw policing in Northern Ireland into reverse gear.

So far, the first minister Peter Robinson and his deputy Martin McGuiness have stood shoulder to shoulder. They postponed a planned visit to the US, after the killing of PC Stephen Carroll, the first officer of the Police Service of Northern Ireland (PSNI) to be claimed by the conflict. Yesterday all political parties spanning the entire spectrum from republicans to loyalists met in Stormont Castle, a unique event. The communities these leaders represent are showing amazing restraint - from the Progressive Unionist counsellor on the Shankill Road who says that retaliation would be playing into the hands of the dissident republicans, to Mr McGuiness who described those responsible for the attacks as traitors to the island of Ireland.

The walls which separate rival communities seem to stand higher in Belfast than they do in Baghdad. And, unlike in Iraq, they are in no danger of coming down soon. Like the bad old days, Belfast is awash with journalists. But the quotes they are reaping are unlike the ones of the past. Has the middle ground of peace widened in the decade since the last attacks were traded with soldiers? That possibility should be borne in mind by those who argue that the peace process rewarded violence and appeased terrorism. It could already have achieved a cross-community consensus unheard of in the province.

There is a quid pro quo in all of this. We cannot welcome the many calls Sinn Féin has made to its own community in the last 24 hours to support the policing service, while at the same time ignoring their opposition to the re-introduction of special forces, like the Special Reconnaissance Regiment. Memories die hard and bitter memories die hardest. After decades of the controversy over the Royal Ulster Constabulary, the province has a police force which many in the unionist community claim is denuded. About 400 officers left the service when the special branch and specialist surveillance units were reconstituted under the PSNI while MI5 was put in charge of counter-intelligence. A lot of old scores were settled between rival security services in the process.

But what the province has gained is a police force with at least the prospect of growing cross-community support. If Sir Hugh Orde, the chief constable of the PSNI gets through to his intended audience, when he appealed for information - and there were already two arrests last night - it will be as a result of the trust the new dispensation has achieved, not a result of high-tech surveillance. Trust will not be maintained by turning the clock back to the days when British special forces treated parts of the province as their favourite hunting ground. Groups such as the Continuity IRA, which claimed responsibility for killing the police officer in Craigavon, are splinters of splinters. They are exactly what Sinn Féin's leaders worked hard to avoid, by taking the whole community with them. The response of the PSNI now needs to take into account republicans as well as loyalists who travelled that long and hard road. Much has been gained in the last decade, so there is now a lot to lose.